Improvement in bush-hammers



UNITED .STATES PATENT OFFICE.

JOHN HARTNOLL, OF MEDFORD, MASSACHUSETTS.

IMPROVEMENT IN BUSH-HAMMERS.

Specification forming part of Letters Patent N o. 153,950, dated August 11, 1374; application liled July 24, 1814.

To all whom it may concern:

Be it known that I, JOHN HARTNOLL, of Medford, in the county of Middlesex, State of Massachusetts, have invented a certain new and useful Improvement in Bush-Hammers, of which the following is a description suliiciently full, clear, and exact to enable any person skilled in the art or science to which my invention appertains to make and use the same, reference being had to the accompanying drawing forming a part of this specification, in which- Figure l is a vertical longitudinal section of my improved hammer; and Fig. a sectional view, showing the formation of the cutters.

Like letters of reference indicate corresponding parts in the diiferent figures of the drawing.

My invention relates to that class of hammers for dressing stone which are known as bush hammers, and which are provided with a series of detachable cutters; and consists of a novel construction and arrangement of the parts, as hereinafter fully set forth and claimed, by which a cheaper and more durable implement of this character is produced than is now in common use. In ordinary bush-hammers of this description the cutters are secured in the head or stock by means of bolts passing through holes drilled in the base of the cutters. This method of construction causes the cutters to work loose and break or crack easily in using, as well as in upsetting or sharpening, and renders them much more expensive. ate these difficulties; and to this end I con- My invention is designed to obvistruct the cutters without bolt-holes, making the cutter-head with dovetail-sockets, and securing the cutters my means of screw-bolts, clamps, andwedges, as hereinafter described.

In the drawing, A is the head or stock of the hammer; B, the cutters; O D, the screwbolts; d d, the clamps; and :v rv, the wedges. The cutters are composed of thin plates of metal, of uniform thickness, and are otherwise of the ordinary construction, except that they are without bolt-holes, and have tenons a at the lower ends, which fit in the base of the socket, and prevent them from moving lateijally therein. The sides of the socket are slightly inclined inwardly or dovetailed; and as it is desirable to have the butts of the cuttersof even thickness with the points, the centrallydisposed wedges a: w are used to separate and form them as a whole into a dovetail-tenon corresponding with the socket, enabling the clamps d d to hold them securely.

- Having thus explained my invention, what I claim is The bush-hammer described, consisting of the head A, clamps d d, bolts C D, cutters. B B, and wedges ma, constructed and arranged to operate substantially as and for the purpose set forth and specified.

JOHN HARTNOLL..

Witnesses:

C. A. SHAW, H. E. METcALF. 

